couchbase/dist/transcoders.js

The official Couchbase Node.js Client Library.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.DefaultTranscoder = void 0;
const NF_JSON = 0x00;
const NF_RAW = 0x02;
const NF_UTF8 = 0x04;
const NF_MASK = 0xff;
const NF_UNKNOWN = 0x100;
const CF_NONE = 0x00 << 24;
const CF_PRIVATE = 0x01 << 24;
const CF_JSON = 0x02 << 24;
const CF_RAW = 0x03 << 24;
const CF_UTF8 = 0x04 << 24;
const CF_MASK = 0xff << 24;
/**
 * The default transcoder implements cross-sdk transcoding capabilities by
 * taking advantage of the common flags specification to ensure compatibility.
 * This transcoder is capable of encoding/decoding any value which is encodable
 * to JSON, and additionally has special-case handling for Buffer objects.
 *
 * @category Key-Value
 */
class DefaultTranscoder {
    /**
     * Encodes the specified value, returning a buffer and flags that are
     * stored to the server and later used for decoding.
     *
     * @param value The value to encode.
     */
    encode(value) {
        // If its a buffer, write that directly as raw.
        if (Buffer.isBuffer(value)) {
            return [value, CF_RAW | NF_RAW];
        }
        // If its a string, encode it as a UTF8 string.
        if (typeof value === 'string') {
            return [Buffer.from(value), CF_UTF8 | NF_UTF8];
        }
        // Encode it to JSON and save that otherwise.
        return [Buffer.from(JSON.stringify(value)), CF_JSON | NF_JSON];
    }
    /**
     * Decodes a buffer and flags tuple back to the original type of the
     * document.
     *
     * @param bytes The bytes that were previously encoded.
     * @param flags The flags associated with the data.
     */
    decode(bytes, flags) {
        let format = flags & NF_MASK;
        const cfformat = flags & CF_MASK;
        if (cfformat !== CF_NONE) {
            if (cfformat === CF_JSON) {
                format = NF_JSON;
            }
            else if (cfformat === CF_RAW) {
                format = NF_RAW;
            }
            else if (cfformat === CF_UTF8) {
                format = NF_UTF8;
            }
            else if (cfformat !== CF_PRIVATE) {
                // Unknown CF Format!  The following will force
                //   fallback to reporting RAW data.
                format = NF_UNKNOWN;
            }
        }
        if (format === NF_UTF8) {
            return bytes.toString('utf8');
        }
        else if (format === NF_RAW) {
            return bytes;
        }
        else if (format === NF_JSON) {
            try {
                return JSON.parse(bytes.toString('utf8'));
            }
            catch (e) {
                // If we encounter a parse error, assume that we need
                // to return bytes instead of an object.
                return bytes;
            }
        }
        // Default to returning a Buffer if all else fails.
        return bytes;
    }
}
exports.DefaultTranscoder = DefaultTranscoder;